The Relationship Between Prostate Volume, Prostate- Specific Antigen and Age in Saudi Men with Benign Prostatic Conditions

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1 African Journal of Urology Vol. 16, No. 4, Original article The Relationship Between Prostate Volume, Prostate- Specific Antigen and Age in Saudi Men with Benign Prostatic Conditions H. A. Mosli 1 and T. A. Abdel-Meguid 2 1 Department of Urology, King Abdul Aziz University Medical City, Jeddah, Saudi Arabia and 2 Department of Urology, El-Minia University, El-Minia, Egypt ABSTRACT Objectives: To assess the relationship between prostate volume (PV), prostate specific antigen (PSA) and age in a cohort of Saudi men from the Urology Department, King Abdul Aziz University Hospital, Jeddah, Saudi Arabia. Methods: Medical records of 447 Saudi men aged years with benign prostatic conditions seen between January 2003 and June 2009, were reviewed, retrospectively. Cases with PSA >10 ng/ml, proven prostate cancer, previous prostate surgery or those who received 5-alpha reductase inhibitors (5-ARIs) were excluded. The study population was categorized into seven successive age groups (20-89 years). The variables of age, PV and PSA were examined. Using mean PV of the years age group and mean PSA of the years age group as reference points, percentage differences in mean PV and mean PSA in subsequent age groups were determined. A p-value <0.05 was considered significant. Findings in Saudi patients were compared to other ethnicities. Results: 447 men were enrolled with mean age 64.2 years, mean PV 35.2 cc (range cc) and mean PSA 2.2 ng/ml (range ng/ml). Overall, 62% (277/447) had PV <30 cc and 8.7% (39/447) had PV 50 cc. Among individual age groups, most men had PV <30 cc, except the years age group where 55.2% (53/96) had PV >30 cc. Percentage differences of PV and PSA in years age group (+150% and +70%, respectively) were lower than in the and years age groups (+187% and +160%; % and +220% for PV and PSA, respectively). All variables demonstrated significant weak correlations; except PV and PSA which showed a significant positive relationship (p <0.0001; r=0.441). Conclusion: PV and PSA are significantly and strongly correlated. PV and PSA in Saudi men are closer to Asian than white ethnicities. Key Words: Prostate, volume, prostate specific antigen, prostatic hyperplasia, Saudi Arabia Corresponding Author: Dr. Taha Abo-Almagd Abdel-Meguid, Department of Urology, King Abdul Aziz University Hospital, PO Box 80215, Jeddah, 21589, Saudi Arabia, tahaaboalmagd@yahoo.com Article Info : Date received: 5/7/2010 Date accepted (after revision): 29/8/2010 INTRODUCTION Prostate volume (PV) varies widely throughout man s lifetime, and in the course of different prostatic diseases, including benign prostatic hyperplasia (BPH) 1,2. Both PV and serum prostate-specific antigen (PSA) are key predictors of clinical progression and response to medical therapy in patients with BPH, thus helping to select the regimen for medical treatment (alpha-blockers, 5-alpha-reductase inhibitors (5-ARI), or their 117

2 combination) PV also has implications in episodes of acute urinary retention (AUR) 12 ; predicts the outcome of trial without catheter (TWOC) after AUR and future need for BPH-related surgery 7,10. Moreover, protocols for transrectal ultrasound (TRUS) guided biopsies and detection rates of prostate cancer (PCa) vary according to different PV and PSA levels 13. Therefore, knowledge of PV and PSA is imperative for understanding the natural history of prostatic diseases, and as criteria for diagnostic and therapeutic decision-making. To our knowledge, the differences in PV in Saudi men among different age groups are unknown. The aim of this study was to assess PV and serum PSA levels in Saudi men with benign prostatic conditions in different age groups (20-89 years), as compared to those reported for men of different ethnicities 4,6, MATERIALS AND METHODS Medical records of Saudi men aged years from the Urology Department, King Abdul Aziz University Hospital, Jeddah, between January 2003 and June 2009 were retrospectively reviewed after institutional review board approval. The indications for evaluation were lower urinary tract symptoms (LUTS) and/or infertility workup and included digital rectal examination (DRE), TRUS determination of PV and serum PSA testing in men 40 years old. Men age 40 years with suspicious findings on DRE, TRUS and/or serum PSA ( 10 ng/ ml) who proved to have benign conditions on TRUS guided biopsies were included in the study. Men with PSA >10 ng/ml, proven PCa, previous prostate surgery or treatment with 5-ARIs were excluded from the study. The study population was categorized into seven successive age groups (20-89 years). Statistical analysis was performed using SPSS software version 11 (SPSS, Inc., Chicago, Illinois), examining variables of age, PV and PSA frequencies in overall population and among different age groups. Using Chi-square test, a 2-tailed P-value <0.05 was considered significant. Correlations of age, PSA and PV were performed using Pearson s correlation coefficient (r). Using mean PV of the years age group and mean PSA of the years age group as reference points, the percentage differences in mean PV and mean PSA in subsequent age groups were determined. PV and PSA findings in Saudi men were compared to those of other ethnic origins in reports entailing comparable study populations 4,6, RESULTS A total of 447 men fulfilling the inclusion criteria were included in the study. The mean age was 64.2 years, mean PV was 35.2 (range 7-184) cc and mean PSA was 2.2 (range ) ng/ml. PV and PSA varied widely over different age groups (Table 1). Frequencies of different PV among age groups are shown in Table 2. Overall, 62% (277/447) had PV <30 cc and only 8.7% (39/447) had prostates 50 cc. Among men aged 40 years, 57.6% (231/401) had PV <30 cc, while only 9.7% (39/401) had prostates 50 cc. Among individual age groups, most men had PV <30 cc, except the years age group where more patients (55.2%; 53/96) had PV >30 cc. In the limited number of patients in the years age group (n = 16) we found 62.5% with PV <30 cc. The percentage differences of PV and PSA in the years age group (+150% and +70%, respectively) were lower than those found in the and years age groups (+187% and +160%; and % and +220%, respectively) (Table 3). Age demonstrated significant (p <0.0001) but weak positive correlations with PV (r=0.306) and PSA (r=0.324). Only PSA and PV showed a significant and strong positive correlation (p <0.0001; r=0.441) (Table 4). Comparing our findings to other studies, PV and PSA values in Saudi men were found to be closer to those of Asian ethnicities 15,16 than European and American white men 4,6,14 (Table 5). 118

3 Table 1: Prostate volume and PSA levels among men of different age groups. Age (years) PV (cc) PSA (ng/ml) * n Group Mean Mean ± SD Range Mean ± SD Range ± ± ± ± ± ± ± ± ± ± ± ± All men* ± ± PV=prostate volume, PSA=prostate-specific antigen. * PSA was determined in men aged 40 years old. Table 2: Frequency distribution of different prostate volumes (PV) among men of different age groups. Age group PV < 30 cc PV cc PV cc PV 50 cc /11 (100%) /35 (100%) /63 (81%) 7/63 (11.1%) 3/63 (4.8%) 2/63 (3.2%) /102 (59.8%) 22/102 (21.6%) 9/102 (8.8%) 10/102 (9.8%) /124 (53.2%) 27/124 (21.8%) 19/124 (15.3%) 12/124 (9.7%) /96 (44.8%) 25/96 (26%) 15/96 (15.6%) 13/96 (13.5%) /16 (62.5%) 2/16 (12.5%) 2/16 (12.5%) 2/16 (12.5%) All men 277/447 (62%) 83/447 (18.6%) 48/447 (10.7%) 39/447 (8.7%) Table 3: Percentage differences in mean PV and mean PSA in consecutive age groups, as compared to the reference points of the and year age groups, respectively. Age (years) PV PSA % difference P* % difference P* RP=13.8 ± 3.1 cc n/a n/a n/a % =.1439 n/a n/a % <.0001 RP=1.0 ± 0.4 ng/ml n/a % < % < % < % < % < % < % = % =.0034 *P-values for the differences of mean PV and mean PSA in consecutive age groups as compared to RP. PV=prostate volume, PSA=prostate-specific antigen, RP=reference point, n/a=not applicable. 119

4 Table 4: Correlations of age, PSA and PV. DISCUSSION Age PV=prostate volume, PSA=prostate-specific antigen, r= Pearson correlation coefficient. PV r p value r p value Age.306 <.0001 PV.306 <.0001 PSA.324 < <.0001 Prostatic size varies significantly throughout man s life. Berry and coworkers found that average prostate weight increased from about 20 grams in men aged 40 years to 38.8 grams in men aged above 80 years 1. PV and PSA are key predictors of clinical progression, response to medical treatment and prostate-related events in patients with prostatic diseases 3-9,18,19. DRE, despite being widely used to identify an enlarged prostate, lacks sensitivity, requires an experienced examiner, and is subject to inter-observer variability 3,20,21. TRUS remains the gold standard for PV measurement, although it is not feasible in all patients because of lack of availability, high cost and patient inconvenience 22. Thus, serum PSA has been extensively studied as a proxy marker to estimate PV 3-9. In a study by Bohnen et al 3, PV >30 cc was found in 52 % of men with PSA ranging from ng/ml and in 65% with PSA ranging from ng/ml. The authors concluded that a serum PSA level >1.5 ng/ml could be a functional cut-off value to recognize men with PV more than 30 cc. A number of studies have shown that risk of BPH clinical progression is maximum in men with PV 30 cc and PSA >1.5 ng/ml 8,9,18,19. In a retrospective study, patients with PV >40 cc who were treated with different alpha-blockers demonstrated increased risk of treatment failure 23. In another study 24, patients receiving tamsulosin and having smaller total PV responded better on flow parameters. According to the BPH guidelines of the European Association of Urology, PV >30 40 cc is an indication for 5-ARI therapy in patients with moderate-to-severe LUTS 11. Thus, patients with bothersome LUTS and PV 40 cc may achieve maximum benefit using alpha-blocker medication, while in those with PV 40 cc, 5-ARI therapy (with or without an alpha-blocker) is appropriate 25. We evaluated the relationship between PV, PSA and age in Saudi men with benign prostatic conditions. To the best of our knowledge, this is the first demographic study reporting on the PV in Saudi men of different age groups. We have chosen 30 cc as cut-off value to dichotomize the PV, because in clinical practice a PV 30 cc is commonly described as an enlarged prostate 26, and it was recognized in several studies as a cut-off for response to medical therapy and clinical progression 9,11,18,19. In our study, 62% of all Saudi men had PV <30 cc while only 8.7% had prostates larger than 50 cc. The reported PVs in our study are clearly smaller than those reported in European 4,14 and American studies 6 involving predominantly white men. Among Saudi men aged 40 years, 57.6% had PV <30 cc and only 8.7% had prostates 50 cc. Comparatively, in a European study from the Netherlands, involving 1859 patients aged years with symptomatic BPH and no evidence of prostate cancer, 26.3% had PV <30 cc and 30.1% had prostates >50 cc 4. Additionally, 55.2% of Saudi men aged years showed a PV >30 cc compared to 83% reported in a similar age group of white men 4. The PV and its relationship to PSA are reported to be variable in different races 4,6, The PV in Japanese 15 and Korean 16 men was reported to be lower than in white men 4,6,14. Additionally, the relationship between PSA and total PV in Asian men is dissimilar to white men where more PSA per unit prostate volume has been noted in Japanese and Taiwanese men 15,17. Of note, the reported mean PSA (5.9 ng/ml) in the study on Taiwanese men 17 was higher than in other studies 4,6,14, including ours. The Taiwanese study was based on biopsy proven BPH in patients who underwent TRUS biopsy due to increased PSA. The authors acknowledged that this was a limitation of their study hindering the applicability of their 120

5 Table 5: Comparison of prostate volume and PSA in Saudi men vs. other ethnicities. Ethnicity Population n [pts] Age [years] mean (range) PV [cc] mean (range) PSA [ng/ml] mean (range) Saudi [Current study] Patients with LUTS secondary to benign prostatic disease and/or infertility (20-89) 35.2 (7-184) 2.2 ( ) White (European) [4] Patients with symptomatic BPH and no evidence of prostate cancer (40-80) 43.9 (9 186) 3.1 ( ) White (European) [14] Patients with LUTS suggestive of benign prostatic enlargement (45-91) Predominantly white (Americans) [6] Patients with symptomatic BPH and no evidence of prostate cancer (40-80) Japanese [15] Patients with at least moderate LUTS and clinical BPH (43-89) 30.2 ( ) 2.3 ( ) Korean [16] Patients with LUTS and BPH (50-79) Taiwanese [17] Patients with LUTS and pathologically proven BPH (42-89) 43.1 ( ) 5.9 ( ) PV=prostate volume, PSA=prostate-specific antigen. data to the general Taiwanese population 17. The PV and PSA values in our Saudi patients were found to be closer to those of Asian ethnicities 15,16 than those of European and American white men 4,6,14. However, the study designs, methodologies and populations involved in these studies are not identical; hence the comparison of such findings should be interpreted with caution. Nevertheless, our findings raise the question whether special PV and PSA cut-off values for medical therapy of BPH are justified in Saudi patients - probably lower than those in white races. Moreover, the results of the current study further support our previous findings 27 questioning the validity of a PSA cut-off of 4 ng/ml for TRUS guided biopsies for prostate cancer detection in Saudi patients and suggesting a lower PSA cut-off value for biopsies. Although traditionally BPH has been considered a chronic and progressive condition 2, some authors have reported on the phenomenon of prostatic atrophy associated with aging in some men 14,28,29. In the Baltimore Longitudinal Study of Aging 28, studying primarily white men without prostate cancer who underwent pelvic magnetic resonance imaging (median age 58 years, range 30-74), the PV increased at a median rate of 0.6 cc per year (range -9.9 to 62.1), corresponding to a median 2.5% annual change. Overall, 61.9% of men had prostate growth, 1.4% had a stable prostate size and 36.7% had a decrease in prostate size during the study period 29. In a Japanese study 29, Tsukamoto et al examined the longitudinal changes in PV in 67 men with LUTS and at least 2 serial TRUS measurements. Prostate volume increased in 70%, remained stable in 15% and decreased in 15% of men 29. Furthermore, Vesely et al from Sweden reported on the relationship between age, PV, PSA, symptom score and uroflowmetry in men with LUTS 14. They reported progressive increase of mean PV (48.2ml) and mean PSA (5.4 ng/ml) in the <80 years age group as compared to the <54 years age group (27.5 ml and 1.5 ng/ 121

6 ml, respectively). Nevertheless, in the years age group they found a decrease in both PV and symptom score, while PSA remained unchanged 14. In our study, the years age group demonstrated a majority (62.5%) with PV <30 cc, denoting smaller prostates in this particular group as compared to the preceding younger 50-59, and age groups, where 59.8%, 53.2% and 44.8% had PV <30 cc, respectively. Additionally, using PV of the years age group and PSA of the years age group as reference points, the percentage differences of PV (+150%) and PSA (+70%) in the years age group are lower than those found in the and years age groups (+187% and % for PV; and +160% and +220% for PSA), respectively. Although these findings can be explained by the hypothesis of prostatic atrophy 14,27,28, our findings cannot necessarily endorse this hypothesis and we caution about their interpretation, as the sample size of the years age group is very small and there is lack of longitudinal follow-up of individual patients. We recognize that our study was limited by its retrospective cross-sectional design and its relatively small single-center study population. The clinical cohort was selected on the basis of symptoms, thus it is not a typical community-based sample. Our findings need to be better characterized by prospective, multicenter, long-term longitudinal studies entailing larger cohorts of randomly selected community-based populations. Conclusions Changes in PV and PSA are highly variable among different ages. Age demonstrated significant but weak positive correlations with PV and PSA. Only PSA and PV showed a significant and strong positive correlation. PV and PSA values in Saudi men were found to be closer to those of Asian ethnicities than European and American white men. Acknowledgments Dr Hani Abd-Alwahhab and Dr Bandar Alhebishi assisted in data collection. REFERENCES Berry SJ, Coffey DS, Walsh PC, Ewing LL. The development of human benign prostatic hyperplasia with age. J.Urol. 1984; Sep;132(3): Emberton M, Andriole GL, de la Rosette J, Djavan B, Hoefner K, Vela Navarrete R, et al. Benign prostatic hyperplasia: A progressive disease of aging men. Urology. 2003; Feb;61(2): Bohnen AM, Groeneveld FP, Bosch JL. Serum prostatespecific antigen as a predictor of prostate volume in the community: The Krimpen study. Eur.Urol. 2007; Jun;51(6):1645,52; discussion Mochtar CA, Kiemeney LA, van Riemsdijk MM, Barnett GS, Laguna MP, Debruyne FM, et al. Prostatespecific antigen as an estimator of prostate volume in the management of patients with symptomatic benign prostatic hyperplasia. Eur.Urol. 2003; Dec;44(6): Lieber MM, Jacobsen SJ, Roberts RO, Rhodes T, Girman CJ. Prostate volume and prostate-specific antigen in the absence of prostate cancer: A review of the relationship and prediction of long-term outcomes. Prostate. 2001; Nov 1;49(3): Roehrborn CG, Boyle P, Gould AL, Waldstreicher J. Serum prostate-specific antigen as a predictor of prostate volume in men with benign prostatic hyperplasia. Urology. 1999; Mar;53(3): Boyle P, Gould AL, Roehrborn CG. Prostate volume predicts outcome of treatment of benign prostatic hyperplasia with finasteride: Meta-analysis of randomized clinical trials. Urology. 1996; Sep;48(3): Roehrborn CG, Boyle P, Bergner D, Gray T, Gittelman M, Shown T, et al. Serum prostate-specific antigen and prostate volume predict long-term changes in symptoms and flow rate: Results of a four-year, randomized trial comparing finasteride versus placebo. PLESS Study Group. Urology. 1999; Oct;54(4): McConnell JD, Roehrborn CG, Bautista OM, Andriole GL,Jr, Dixon CM, Kusek JW, et al. The long-term effect of doxazosin, finasteride and combination therapy on the clinical progression of benign prostatic hyperplasia. N.Engl.J.Med. 2003; Dec 18;349(25): AUA Practice Guidelines Committee. AUA guideline on management of benign prostatic hyperplasia (2003). Chapter 1: Diagnosis and treatment recommendations. J.Urol. 2003; Aug;170(2 Pt 1): Madersbacher S, Alivizatos G, Nordling J, Sanz CR, Emberton M, De La Rosette JJMCH. EAU 2004 guidelines on assessment, therapy and follow-up of men with lower urinary tract symptoms suggestive of benign prostatic obstruction (BPH guidelines). Eur.Urol. 2004;46(5):

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